Successive cold years drove the Vikings out of Greenland, where many of the Medieval Viking villages remain buried under snow and ice to this day.

FORBES: In Which We Gently Correct James Taylor

Dr. LEVINE: Well, I think the key aspect of Viking was a very strong, dedicated team of scientists and engineers and project managers that lived, 24 hours a day, the Viking mission.

NPR: Revisiting the Viking Missions to Mars